Container for fluid products



Aug. 25, 1964 o. F. ECKLUND 3,145,899

CONTAINER FOR FLUID PRODUCTS Filed Dec. 28, 1961 BY MR M ATTORNEYS United States Patent O 3,145,899 CONTAINER FOR FLUID PRODUCTS Oscar Frederick Ecklund, Barrington, Ill., assignor to American Can Company, New York, N.Y., a corporation of New Jersey Filed Dec. 28, 1961, Ser. No. 162,769 4 Claims. (Cl. 229-14) This invention relates to liquidproof paper or fibreboard containers for fluid products and has particular reference to forming a cup-like element of moisture impervious film and to seal it to the inside end of a container body and/ or onto the folded end flaps at the end of the container to protect exposed raw edges of the end flaps against wicking of the contents into the fibre stock.

Fibre containers are particularly desirable for the packaging and shipment of fiuid products because they are relatively inexpensive to manufacture. However, fibre and paperboard is highly absorbent to fluids and hence must be treated to render them impervious to the contents which are to be filled into them. It has been common practice to treat or line the inner wall or surface of a fibre body structure. However, even when so lined, the raw edges at the ends of the body structure such as the folded end flaps or closure elements often become exposed and act like wicks in absorbing the fluid products from within the container, resulting in weakening of the folded end flaps and eventually leaking of the product. Numerous attempts to protect these raw edges and to render them wickproof have been made, such as dipping the raw edges of the end flaps in molten wax or other impervious compound, and flooding the entire bottom and/or top with molten wax. These methods of protecting the raw edges of container bodies, however, require additional operations which tend to slow down production and add to the cost of a competitive article.

The present invention is directed to overcome the problem of wicking or capillary attraction of the container contents by forming and applying a cup-like element of moisture impervious film to the interior of a container, which element is sealed to both the body structure and the folded container end flaps or, if desired, to the body structure only, and which will thus serve as a barrier in preventing the fluid contents from coming into contact with exposed raw edges of the end flaps at the bottom end of a container.

An object of the invention in the provision of a liquidproof container having an inner seal in the end of a fibre container during the sealing of a plurality of end closure flaps at the end of the container body to protect any raw edges of the end flaps against wicking.

Another object is the provision of such a container wherein a film of moisture impervious material overlaps the interior wall surfaces of the end flaps in a bottom end of a container to protect any exposed raw edges thereof against wicking and to strengthen the bottom end structure of the container.

A further object is the provision of such a container wherein a cup-like element is formed of moisture impervious film and is secured to the interior wall of a container body to protect any exposed raw edges of the cut ends of the folded end flaps against wicking of the fluid contents into the fibre stock.

Another object is the provision of a liquidproof container wherein a film of impermeable material is secured to the inner bottom end portion of the container to provide an interior seal between the container body and the folded end flaps, simultaneously with the sealing of the folded end flaps together in overlapping relation.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

FIGURE 1 is a perspective view illustrating a container having folded end flaps prepared in accordance with the method steps of the present invention with parts broken away;

FIG. 2 is a perspective view showing a rectangular strip of moisture impervious film positioned on the top face of a mandrel preparatory to being inserted into the end of a container body shown in superimposed position thereabove;

FIG. 3 is a perspective view of a container body with a corner thereof broken away and illustrating the method step of folding the marginal edge portions of the film over the top edge of the mandrel to form the film into a cuplike element and to insert it into the container;

FIG. 4 is a view similar to FIG. 3 illustrating the container fully mounted on the mandrel and showing the shallow cup-like element in position adjacent the line of fold of the end flaps at the upper end of the container body; and

FIG. 5 is a sectional view of the parts shown in FIG. 4 with the container end flaps disposed in folded overlapped relation and a sealing head positioned thereabove for sealing the parts together in an end joint.

As a preferred or exemplary embodiment of the instant invention the drawings illustrate a container and a method of producing the same by forming a film of moisture impervious material into a shallow cup-like element over the end of a mandrel and inserting and positioning it in an end of a container where it is secured during the sealing of the container end flap or closure elements at the end of the container.

The container provided for the above purpose is tubular in form and preferably is square or rectangular in its transverse cross-section. For the purpose of this invention the container comprises a body 11 formed from a single sheet of lined fibrous material, of approximately .012 to .022 inch in thickness. The container body is creased along a plurality of parallel and spaced apart lines which are folded at right angles to provide four side Walls 12 of the container (FIGS. 2 and 3). The opposite edges of the sheet are joined in a lap seam joint 13 which extends longitudinally of the body along one corner thereof. The lap seam joint 13 is secured together by any suitable moistureproof or liquidproof adhesive.

The container body 11 is provided with a plurality of end flaps or closure elements which extend from one end of each of the side walls 12 for closing one end of the container, which end preferably constitutes the bottom. Hence, for this purpose two of the opposing side walls 12 are provided with a pair of inner end flaps 14. The intermediate side walls 12 are provided with a pair of outer end flaps 15 which preferably are longer than the inner end flaps 14 so that their outer edges may be overlapped and sealed together.

The lined fibrous material from which the container bodies 11 are formed preferably is of a film laminated fibre or paperboard stock having an inner and outer lining of thermoplastic material such as polyethylene film having a thickness of approximately .001 to .003 inch. It is also understood that other forms of impervious linings or coatings such as hot melt material and resin emulsion coatings may be used. The coating or lining of the fibrous material preferably is done prior to cutting the material into blanks.

A film of flexible impermeable material such as coated fibre, metal foil, e.g. aluminum, thermoplastic material formed from a polymerized olefin material, for example polymers and copolymers of vinyl chloride and/ or polyethylene with the last being preferred, is selected for sealing the inner end of the container. This film is in the form of a square or rectangular blank 16 having a thickness of approximately .001 to .003 inch in thickness (FIG. 2). The film blank 16 is cut larger than the crosssectional dimension of the container so that when the blank is formed into cup-shape it will have a surrounding flange of approximately /2 inch in height to insure sufficient overlapping along the edges on the interior of the container end joint.

With the container body formed into tubular shape and the film blank cut into a rectangular configuration as hereinbefore described, the parts may now be assembled in accordance with the steps of the present invention. This is accomplished by first placing a film blank 16 onto the upper flat surface 17 of a mandrel 18. Such a mandrel has the same configuration as the container 11 and hence is also rectangular in its transverse crosssection (FIG. 2).

With the parts disposed in axial alignment as best illustrated in FIG. 2, relative movement between them will effect their being assembled. For the purpose of this invention and without undue limitation thereof, it is preferred that the container 11 be moved relative to the film blank 16 disposed on the mandrel. Hence as the container 11 is moved downwardly, the lower or leading edge of the body engages the outer marginal edge portions of the film blank extending beyond the upper edge of the mandrel 18 and folds them over the four side edges. Further movement wipes them downwardly in overlapping relation on the side walls of the mandrel as surrounding flanges 19, which are creased and/ or overlapped at each of the four corners as at 21 (FIG. 3). This folding, creasing and downward wiping action thus forms the film blank 16 into a shallow cup-like element 22.

As the container body 11 continues to move downwardly over the mandrel 18, the cup-like element 22 gradually is slid through the container body to position it in an end thereof. This desired position is reached when the container body 11 is fully mounted on the mandrel 18, at which time, the upper face of the film cup-like element is substantially flush with a line of fold 23 (FIG. 4). It is along this line of fold that the inner and outer end flaps 14, 15 are integrally joined to the container body.

The next step of the present invention is the positioning or folding of the inner and outer pairs of end flaps at one end of the container body 11 in overlapping relation upon each other and upon the cup-like element 22 disposed in the end thereof. FIG. 1 of the drawings illustrates a preferred arrangement of these parts as they are brought together for asembly on the mandrel 18. The container parts now are ready for the final step of sealing them in an end joint. For this purpose the assembled parts, together with the mandrel, are moved in any suitable manner into engagement beneath a sealing head 24 (FIG.

The sealing head 24 is formed so that it will have contacting engagement with both the exterior wall surface of the outer end flaps 15 and also the surrounding side walls 12 of the container body for applying heat to the container parts for sealing them together. The head 24 thus is provided with an electrical heating element 25 which is connected to any suitable electrical source for heating the head. While the drawing illustrates the heat as being supplied by a so-called hot tool or sealing head, it is also understood that other heating means may be substituted such as high-frequency current or dielectric heating.

It will be readily seen that as the heat is applied to the container parts, the film laminated fibre stock of the inner and outer pairs of end flaps are sealed together, and the cup-like element 22 is sealed to both the container body and also to the interior wall surface of the inner end flaps 14 simultaneously. Specifically, in the present invention the inner and outer pairs of end flaps 14, 15 are heat sealed together at one end of the container while the cup-like element 22 has its flanges 19 sealed to the inner marginal edge portion of the container body and the panel wall part thereof sealed to the inner wall surfaces of the inner end flaps 14. Hence by this method the cup-like element 22 completely overlaps and seals the raw cut edges of the end flaps at the end of the body.

If desired, however, sealing of the cup-like element 22 inside the container may be limited only to scaling of the flanges 19 to the inner marginal edge portion of the container body. In such instances of sealing, only a limited or controlled amount of heat is applied to the central portion of the sealing head which is sufficient to seal the outer end flaps 15 to the inner end flaps 14 while a greater de gree of heat is applied to the peripheral portions by the heating element 25, in which case the panel wall of the cup-like element 22 is not sealed to the interior wall surfaces of the inner end flaps 14.

In order to fully insure complete sealing of the creased and overlapped portions of the flanges 19 at the corners 21 of the cup-like element 22, the film 16 may be coated with wax or other hot melt non-toxic, inert material. Hence, during the sealing all folds and/or creases are sealed together at the corners in the end of the container body in a leakproof, non-wicking end seam joint.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction, and arrangements of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A container for fluid products, comprising:

a coated fibre container body having a plurality of end flaps extending and overlapping each other from at least one end of said container body for complete closing and sealing an end thereof;

a cup-like element formed of a liquid impermeable film having a panel wall and a continuous surrounding flange wall, said element disposed within the container and having said panel wall engageable with and secured to an inner wall surface of at least one end p;

and said flange wall extending inwardly from said end flaps along the interior wall surface of said container body and being engageable with and heat sealed to only said interior container wall surface, and the edge of said flange wall terminating on a line spaced from the juncture of said end flaps with said container body thereby protecting raw edges of said end flaps at the end of the container body against capillary attraction of the fluid contents into the fibre stock.

2. The container as defined in claim 1 wherein the container body and the pairs of inner and outer end flaps extending from an end of the container body are made of a single layer of paperboard stock having at least the interior Wall surfaces thereof coated with a plastic film.

3. The container as defined in claim 1 wherein the container body and the pairs of inner and outer end flaps extending from an end of the container body are made of laminated paperboard stock having at least the interior wall surfaces thereof coated with a plastic film.

4. The container as defined in claim 1 wherein the container body and the pairs of inner and outer end flaps extending from an end of the container body are coated with polyethylene.

References Cited in the file of this patent UNITED STATES PATENTS Brooks Jan. 20, 1948 Benzon-Petersen June 11, 1957 Zerlin July 16, 1957 Ingham Aug. 6, 1957 Burke June 3, 1958 Moore Sept. 1, 1959 Turpin Aug. 15, 1961 FOREIGN PATENTS Norway Apr. 13, 1959 

1. A CONTAINER FOR FLUID PRODUCTS, COMPRISING: A COATED FIBRE CONTAINER BODY HAVING A PLURALITY OF END FLAPS EXTENDING AND OVERLAPPING EACH OTHER FROM AT LEAST ONE END OF SAID CONTAINER BODY FOR COMPLETE CLOSING AND SEALING AND END THEREOF; A CUP-LIKE ELEMENT FORMED OF A LIQUID IMPERMEABLE FILM HAVING A PANEL WALL AND A CONTINUOUS SURROUNDING FLANGE WALL, SAID ELEMENT DISPOSED WITHIN THE CONTAINER AND HAVING SAID PANEL WALL ENGAGEABLE WITH AND SECURED TO AN INNER WALL SURFACE OF AT LEAST ONE END FLAP; AND SAID FLANGE WALL EXTENDING INWARDLY FROM SAID END FLAPS ALONG THE INTERIOR WALL SURFACE OF SAID CONTAINER BODY AND BEING ENGAGEABLE WITH AND HEAT SEALED TO ONLY SAID INTERIOR CONTAINER WALL SURFACE, AND THE EDGE OF SAID FLANGE WALL TERMINATING ON A LINE SPACED FROM THE JUNCTURE OF SAID END FLAPS WITH SAID CONTAINER BODY THEREBY PROTECTING RAW EDGES OF SAID END FLAPS AT THE END OF THE CONTAINER BODY AGAINST CAPILLARY ATTRACTION OF THE FLUID CONTENTS INTO THE FIBRE STOCK. 